A connector housing of an electrical connector is fabricated through injection molding of an electrically insulating synthetic resin. Warpage commonly occurs on an injection-molded product due to stress occurring inside the molded product. When warpage occurs on the connector housing, defective conditions, for example, insufficient assembling accuracy to a chassis or impossibility of mating with a mating connector housing, occur.
To reduce warpage of the connector housing, as disclosed in Japanese Patent Application No. 2007-87874 A, a wall part on which the warpage occurs is increased in thickness as compared with other parts. Increasing the thickness is effective for reduction of the warpage of the connector housing, however, in some applications of the connector housing, an increase in thickness alone is insufficient to reduce warpage. In particular, in a case where the connector housing has a large dimension in the width direction and includes a plurality of mating parts that are mated with mating electrical connectors, it is difficult to compensate the warpage.